Steam-boiler.



' W. A. MOFFAT.

STEAM BOILER.

APPLICATION FILED JULY I2, I9I3.

Patented Dec. 28, 1915.

3 SHEETSSHEET l.

ambawto'o y/Z MZ W. A. IVIOFFAT.

STEAM BOILER.

APPLICATION FILED JULY l2, 19x3.

Patented Dec.- 28, 1915.

3 SHEETS-sugar 2.

W. A. MOFFAT.

STEAM BOILER.

APPUCATION FILED JULY 12. I913.

WALTER A. IVIOJFFAT, OF ERIE, PENNSYLVANIA.

STEAM-BOILER.

Specification of Letters Patent.

Patented Dec. 23, 1915.

Application filed July-12, 1913. Serial No. 778,767.

To all whom it may concern Be it known that I, WALTER A. MOFFAT, acitizen of the United States, residing at Erie, in the county of Erieand State of Pennsylvania, have invented new and useful Improvements inSteam-Boilers, of which the following is a specification.

This invention relates to improvements in steam boilers and hasparticular application to means for heating the feed water.

In carrying out the present invention, it is my purpose to provide asteam boiler wherein the water surfaces in contact with the heat ofcombustion will be divided in such manner as to produce an efficient andeconomical boiler and one wherein the feed water will be heated to anydesired degree of temperature preparatory to entering the steam drums ofthe boiler.

It is also my purpose to provide a steam boiler wherein the feed waterwill be initially heated from the Waste heat of the boiler and thensubjected to the heat of combustion in a separate fire box and heated toand beyond the temperature of .the saturated steam employed in thecylinders of the prime mover, the feed water after passing through thisstage being delivered to a storage reservoir under the impulse of itsown steam and thence fed to the main steam drums of the boiler in thesame manner and evaporated in the usual way, thus enabling the ordinaryheating surfaces of the boiler to more easily perform their rating,owing to the fact that the greatest heat of the fire box is not utilizedto heat the feed water to the ordinary temperature of the steam.

l/Vith the above and other objects in view, the invention consists inthe construction, combination and arrangement of parts hereinafter setforth in and falling within the scope of the claims.

lln the accompanying drawings; Figure 1 is a View in front elevation ofa steam boiler constructed in accordance with the present invention,parts being shown in section. Fig. 2 is a vertical longitudinalsectional view taken through the boiler, parts being shown in elevation.Fig. 3 is a top plan view of the boiler, the connections between thecombustion chambers and the stack being shown in section. Fig. 4 is afragmentary perspective'view showing the drums and the connectionsbetween the same on an enlarged scale.

Referringnow to the accompanying drawings in detall, A designates afurnace composed of a plurality of independent oombustion chambers 1,three of such chambers being shown in the present instance. Arrangedwithin each combustion chamber 1 1s a bank of water tubes 2 having theopposite ends thereof connected with vertlcal headers 3 disposed at theopposite ends of the combustion chamber. Sui-mounting the outercombustion chambers 1, 1 are the steam drums 4, 4 each having theopposite ends thereof connected with the headers 3, 3 wlthin theparticular combustion chamber. Surmounting the central combustionchamber and disposed in a plane above the steam drums 4, 4 is a storagedrum 5 havmg the opposite ends thereof resting upon cross boxes 6 seatedupon the top wall of the combustion chamber and connected with theheaders 3, 3 therein through the medium of suitable tubes or pipes. Thestorage drum 5 is preferably mounted above the drums 4 such a distancethat the low water line of the storage drums corresponds with the highwater line of the steam drums.

Surmounting the storage drum 5 is a feed water drum 7 having theopposite ends thereof resting upon and in open communication with crossboxes 8 disposed above thestorage drum and in communication with theboxes 6 through the medium of pipes or tubes 9. By means of thisconstruction,

it will be seen that the contents of the steam drums are heated from theheaders and bank of tubes within the respective combustion" chambers,while the bank of tubes and the headers within the central combustionchamber take care of the contents of the feed water drum. 7

A water supply pipe 10 is tapped into one end of the feed water drum 7adjacent to the bottom thereof and is connected up with a feed Waterheater heated from any and all sources of waste heat of the boiler.llhis supply pipe is provided with a controlling valve 11 and a checkvalve 12, the latter permitting the water to enter the feed water drumand preventing back flow. Leading out of one end of the feed Waterdrumad jacent to the bottom thereof is a water tion between the drums and 7may be readily established and cut off. Pipes 15,

each has the lower end connected with one vided with a manually operablecontrolling valve 17 whereby communication between the water spaces ofthe storage and steam drums may be conveniently established and cut off.Each pipe 15 is equipped with a check valve 18 whereby the water mayfiow from-the storage drum to the steam drums and back flow eliminated.A steam pipe 19 has one end thereof connected to one end of the feedwater drum adjacent to the top thereof and the opposite end connectedwith the steam space of feed water heater so that the pressure withinthe feed water drum and feed water heater may be equalized, such steampipe being provided with a manually operable controlling valve 20. a

In operation, the valve 14 in the pipe 13 is shut off so thatcommunication between the feed water drum and the storage drum is cutoff, while the valves 11 and 20 in the water supply pipe 10 andequalizing steam pipe 19 are opened and the water from the feed waterheater permitted to flow into the drum 7, the valve 20 being closedsucceeding the filling of the drum 7. When the water in the drum 7 hasbeen sufliciently heated, incident to circulating through the headersand banks-of water tubes in the particular combustion chamber, the valve14: is opened so that the Water within the feed water drum will be blowndown into the s'orage drum 5. The feed water drum is preferably providedwith a safety valve 21, while the steam drums are provided with similarvalves 22,

the storage drum being also equipped with a. similar safety valve 23.The valve 21 of the feed water drum responds only when the pressurewithin such drum is greater than that required to open the valves of thesteam drums. When necessary, the pressure between the steam drums andthe storage drum is equalized so that the'water within the storage drumwill gravitate into the water space of the steam drums by way of thepipes 16 and 15 and maintain the water level in the steam drums tocompensate for evaporation. For this purpose, I employ pipes 24, 24 eachhaving one end tapped into the steam space of one of the steam drums,while the free ends of such pipes are interconnected .by means of ahorizontal pipe section'25 tappedinto the steam space of the ,storagedrum, the pipes 24, 24 being provided with manually operable controllingvalves 26 whereby the communication between the steam spaces of thesteam drums and the storage drum for equalizing the pressure may bereadily controlled. The numeral 27 designates a steam equalizing pipehaving one end connected with the steam space of the storage drum andthe opposite end tapped on to the steam pipe 19 immediately adjacent tothe connection between the latter and the feed water drum so that thepressure within the drums 5 and 7 may be equalized, the pipe 27 beingpro vided with a controlling valve 28.

Under normal conditions, the pressure in the feed water drum issufficient to blow the heated water into the storage drum by way of thepipe 13 connecting said drums when the valve 14 is open, while thepressure in the storage drum, being greater than that in the steam drumsblows the water from the storage drum into the steam drums. In someinstances, the storage drum may be filled to its capacity and in thiscase, the feed water drum 7 is placed in open communication with thesteam spaces of the steam drums thus making the feed water drum, ineffect, a part of the main boiler and permitting the steam to-flow fromthe feed water drum into the steam drums. For this purpose pipes 29, 29each has the lower end thereof tapped into the steam space of one of thesteam drums while the free extremities of such pipes are connectedthrough the medium of a horizontal pipe section 30, the latter beingconnected with the steam pipe 19 at the point of connection between thelast-named pipe and the pipe 27. The pipes 29 are equipped with manuallyoperable controlling valves 31 whereby communication between the steamspaces of the steam drums and the feed water drum may be established andcut off. Subsequent to the water flowing into the storage drum from thefeed water drum, as previously described, the valves 26, 26 in the pipes24;, 24 are opened so that the steam spaces of the drums 4, 4 and thestorage drum will be in communication, thereby permitting the waterwithin the storage drum to continuously gravitate into the water spacesof the steam drums by way of the pipes 16 and 15, and the steam to flowthrough the pipes 24:, 24, the valve 17, of course, being open, theweight of the water opening the check valves 18. Thus, it will be seenthat the water and steam will flow continuously into the steam drums asthe steam is consumed. In the event of the feed water drum being filledto its capacity and steam generating in the feed water drum, the valves31, 31 in the pipes 29, 29 are opened so that the steam within the steamspace of the feed water drum will flow into the steam spaces of thesteam drums, incident to the safety valve of the feed water drumresponding to a higher pressure than that required to open the similarvalves of the steam drums. It

will, of course, be understood that each drum is equipped with the usualWater glass and pressure gage and blow-off valves.

The numeral 32 designates a smoke stack common to the combustionchambers and each combustion chamber is provided with a damper wherebycommunication between the same and. the smoke stack may be controlled.In order to economize in fuel and heat the air previous to the latterpassing between the bars of the grates in the combustion chambers andthrough the fuel on such grates, I employ a conduit 33 disposedconcentrically of the smoke stack 32 and spaced apart therefrom asuitable distance. Leading from the conduit 33 at diametrically oppositepoints are air conveying pipes 34 disposed at the opposite sides of thefurnace structure A and having the free ends thereof connected with anair pipe 35 passed transversely through the ash pits of the combustionchambers and provided with suitable discharge openings below the gratesso that the air may be.discharged through the latter. From thisconstruction, it will be seen that when all the entrances to the ashpits and fire boxes are closed, the column of.

. connection with the, accompanying drawings,

the construction, mode of operation and manner of employing my inventionwill be readily apparent. It will be seen that I have provided a steamboiler wherein all the heating surfaces are converted into boiling areasthereby increasing the efficiency and capacity of the boiler andcentralizing the scaledeposits, while the feed water is thoroughly andefliciently heated preparatory to entering the steam drums so thatexpansion and contraction of the latter, incident to cold feed water islargely avoided.

While I have herein shown and described one preferred form of myinvention by way of illustration, I wish it to be understood 7 that I donot limit or confine myself to the precise details of constructionherein described and delineated, as modification and variation may bemade Within the scope of the claims without departing from the spirit ofthe invention.

I claim:

1. In a steam boiler, a steam drum, :1 storage drum designed to maintaina greater pressure than said steam drum and located at a greateraltitude than said steam drum,

WEI:

a feed water heating drum disposed above said storage drum and designedto maintain a pressure greater than that of said storage drum,connections between said feed water heating drum and storage drumwhereby the water may be delivered to said storage drum succeeding thepreliminary heating thereof and under the pressure of said feed waterheating drum, and connections between said storage drum and steam drumwhereby the water will be fed from said storage drum to said steam drumunder the pressure in said storage drum.

2. In a steam boiler, a steam drum, a storage drum designed to maintaina greater pressure than said steam drum and located at a greateraltitude thansaid steam drum, a feed water heating drum disposed abovesaid storage drum and designed to maintain a pressure greater than thatof said storage drum, connections between said feed water heating drumand storage drum whereby the water may be delivered to said storage drumsucceeding the preliminary heating thereof and under the pressure ofsaid feed water heating drum, connections "between said storage drum andsteam drum whereby the water will be fed from said storage drum to saidsteam drum under the pressure in said storage drum, and means forconnecting the upper portions of said feed water drum and storage drumto equalize the pressures therein.

3. In a steam boiler, a steam drum, a storage drum designed to maintaina greater pressure than said steam drum and located at a greateraltitude than said steam drum, a feed water heating drum disposed abovesaid storage drum and designed to maintain a pressure greater than thatof said storage drum, connections between said feed water heating drumand storage drum whereby the water may be delivered to said storage drumsucceeding the preliminary heating thereof and under the pressure ofsaid feed water heating drum, connections between said storage drum andsteam drum .whereby the water will be fed from said storage drum to saidsteam drum under the pressure in said storage drum, means for connectingthe upper portions of said feed water drum and storage drum to equalizethe pressures therein, and means .for connecting the steam space of saidsteam drum with the upper portion of said storage drum to' equalize thepressures therein.

4. In a steam boiler, a steam drum, a storage drum designed to maintaina greater pressure than said steam drum and located at a greateraltitude than said steam drum, a feed water heating drum disposed abovesaid storage drum and designed-to maintain a pressure greater than thatof said storage drum, connections between said feed water heating drumand storage drum whereby the water may be delivered to said storage drumsucceeding the preliminary heating thereof and under the pressure ofsaid feed water heating drum, connections between said storage drum andsteam drum whereby the water will be fed from said storage drum to saidsteam drum under the pressure in said storage drum,v means forconnecting the upper portions of. said feed water drum and storage drumto equalize the pressures therein, means for connecting the steam saidstorage drum and designed to maintain a pressure greater than that ofsaid storage drum, connections between said feed water heating drum andstorage drum whereby the water may be delivered to said storage drumsucceeding the preliminary heating thereof heating drum, connectionsbetween said and under the pressure of said feed water storage drum andsteam drum whereby the water will be fed from said storage drum to saidsteam drum under the pressure in said storage drum, and means forplacing the upper portions of all of said drums in communication withone another to equalize the pressures therein when conditions warrant.

In testimony whereof I afiix my signature in presence of two witnesses.

WALTER A. MOFFAT.

Witnesses:

E. 'EoMoNs'roN, Jr., JOHN J. MCCARTHY.

